The present invention relates generally to modular caissons for use in constructing, expanding and modernizing ports and harbors, and more particularly to modular caissons which are constructed, in whole or in part, onshore and then floated to a preselected site, trimmed and ballasted down, and combined with other caissons to form marine structures and integrated marine structures/marine terminals.
There is a growing need to construct new ports and harbors and to expand or modernize existing ports and harbors. For example, in emerging market countries, there is the need for construction of new modern port and harbor facilities. For military and naval use, there is also a need for prefabricated, "instant" ports for the rapid deployment of forces, equipment and cargo at locations where port facilities are inadequate or non-existent. Existing ports and harbors must be periodically dredged to maintain them operational, and there is a heightened awareness of the environmental dangers posed by contaminated dredge material. This, in turn, has severely restricted the dredging of ports and harbors and has prevented the expansion and modernization of port and harbor facilities. There are now worldwide concerns , as well as international laws, prohibiting the dumping of contaminated dredge materials in the open ocean.
An example of the environmental and economic significance of contaminated dredge material recently occurred in New York Harbor. Having just completed construction of the Howland Hook Container Terminal, it was found that the material from dredging down the dock was so heavily contaminated with heavy metals, PCB's, dioxins, etc., that the only solution to disposing of this material (with open ocean dumping no longer allowed under the London Dumping Convention) was to ship it by train to a dump in Utah, a distance of over 2000 miles away at a cost exceeding $100/cubic yard--over 20 times the previously available cost when ocean dumping was available.
World trade patterns are changing rapidly in the post cold-war, post industrial age. Certain of these changing patterns will dominate for the foreseeable future:
(1) Trans-Pacific trade will far exceed, and continue to grow more rapidly, than trans-Atlantic trade.
(2) North/South trades in the western Pacific and western Atlantic oceans will become dominant trade routes in their own right.
(3) As a result of (1) and (2), there will be relatively less need to transit the Suez and Panama Canals, especially the Panama Canal with its relatively shallow 40 foot draft constraint.
These changing world trade patterns will result, from a marine standpoint, in the need to:
(1) Expand and/or modernize many older ports in industrialized nations if they are to remain competitive. This includes the United States where ports such as New York are increasingly outmoded by modern standards.
(2) Construct new ports in emerging market countries such as China, Indonesia, India, Brazil, Argentina and the countries of the former Soviet Union including Estonia, Ukraine, Georgia and Russia itself. Many of these potential port sites lie in remote areas away from industrial centers.
Ports and harbors have traditionally been constructed as stand-alone, one-of-a-kind, projects. First breakwaters, piers, wharves etc. are constructed and subsequently marine cargo terminals are erected on these marine structures, etc. No standardized methods have been developed to alter this relatively high cost, one-of-a-kind, method of construction.
Modernization of older port cities (whose depths were geared to the 40 feet and 45 feet draft constraints of the pre-World War II Panama and Suez Canals) requires them to now seek deeper water sites if they are to remain competitive. This is not as easy as it may seem. For example, the Port of New York is no longer able to receive the largest fully loaded container ships (or tankers) now in standard use, despite having spent $250 million in an attempt to deepen the Kill Van Kull channel leading to its largest container port and almost all of its oil terminals. This massive expenditure in dredging funds was mostly wasted as the Kull still remains too shallow by today's standards.
The problem is compounded by the port being originally sited on a shallow estuary and further compounded by a relatively shallow offshore continental shelf. For the Port of New York to find a deep-water site for a port may well involve moving offshore to a man-made island, much as the-Port of Rotterdam did when it built the "island" of Maasvlacht in the North Sea.
In certain cases, even in emerging countries, the problems of modernizing an existing major port are compounded by the original port having been located on relatively shallow water. For example, Tanjung Priok, the port of Jakarta on the island of Java, is one such case. Any modernization of this port will have to be undertaken out in the Java Sea because of the shallow shelf lying off the north coast of the island of Java.
With respect to the construction of new ports in emerging market countries, the problem is not so much the shortage of land with potential for deep-water port sites, but rather their remote location. For example, the two planned ports on the Kra Isthmus between Malaysia and Thailand are a case in point. Such sites are far from centers where port construction equipment, supplies and the necessary amount of skilled labor are available, and port construction has traditionally been a labor intensive undertaking. Before the port of Cam Ranh Bay was built in Vietnam it was in a similarly remote region.
In order to solve such major and growing problems, and in order to be cost-effective, it is necessary to develop an industrialized method for constructing, expanding or modernizing ports and harbors. Any such method, however, has to encompass all of the following:
(1) That it be modular in nature, with the modular components being pre-fabricated in existing shipyards and/or shipyard type facilities onshore.
(2) That the modular components be floatable, and have a naval architecture and marine engineering configuration that enables them to be towed (and/or pushed) by sea-going tugs, without other assistance, to installation sites, both near and far even under Beaufort Scale 4-5 conditions.
(3) That the single modular components are designed to be constructed either as monolithic structures (for use where draft constraints do not present a problem); or as sections that can be assembled one with another (for use at locations where draft constraints do present a problem).
(4) That the modular components be ballastable down and up and also precisely trimmable through the use of internal trim and ballast tanks and internal pumps, motors, piping and computer controls--thus obviating any need to use floating dry-dock type facilities in their launching or for their deployment to, or at, installation sites.
(5) That the modular components be designed and constructed so as to be capable of combining, within single integrated modules at installation sites, all of the following functions: Wave and weather protection; marine structure requirements; and intermodal (and/or intramodal) cargo handling, storage and transfer facilities for all types of cargos.
(6) That the modular components be able to contain, in an environmentally secure manner, contaminated materials including contaminated dredge material, either for long-term "entombment" and/or for subsequent decontamination.